idle trouble

OK, here's the story.

I have a 1303 s super beetle with a 1600 engine.

It had a 009 distributor and it ran fine, BUT following the motto "If it ain't broken, you can still try to improve it" I exchanged the 009 for the SVDA distributor.

Reajusted timing to 7,5 before tdc, and reajusted the carb to the specs in my manual.

But now when running idle for about 15 seconds the idle drops from 1000 rpm to something like 500 rpm, and after that it will struggle and die.

Also when I have to stop for traffic lights and I'm going from

80 km/h to zero the rpm drop to 500 also, but this could be the same thing as described when running at idle at standstill.

I checked the vacuum, it moves the breaker points plate and it retains it's vacuum.

What's wrong, do I have to do my reajustments again? I find it strange that it runs relatively fine at idle for a while and then falls back in rpm, quite suddenly.

Any suggestions?

Greetings, Gerrelt

'73 1303 s

Reply to
beetle boy
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...........................I'd richen the idle mixture & see if that helps.

Reply to
Tim Rogers

Wrong model vacuum unit for the carb you are using, or worn/dirty distributor, or centrifugal mechnism spring pre-load too weak, or,or, or.. Maybe the distributor shaft doesn't move freely and it won't return back to "zero" position after coming down from high revs, until after said 15 seconds.. have seen it happen many times. "The revs stay above idle until at some point they just drop down to normal idle speed". Usually the rotor just wouldn't return back all the way after advancing. In mosta cases the reason was the centrifugal mechanism spring. (Virtually no pre-tension)

Jan

Reply to
Jan

That's the same car I drive everyday, except that i wouldn't change my 009 for nothing. Please tell me if I'm wrong, but I think there were two timing settings for 1973 models, one for pre spring '73 (I think 5 ATDC) and one for '73-'74 models (7.5 BTDC). I'm not sure of that one, and really would like to know, so your help is really welcome.

Besides that, did you check for a clogged idle jet? sometimes the problem is so obvious we just forget to check. So clean up everything and then we'll see.

Reply to
Karls Vladimir Peña

Basically this depends on the distributor there is in the car. If it is = a SVDA distributor (single vacuum hose from the carb to the distributor vacuum can), the setting is 7,5 deg BTDC. If it has two vacuum hoses, the setting is 5 ATDC. If it has no vacuum unit (like 009), you set it by maximum advance.

Reply to
Olli Lammi

Thanks Olli

Basically this depends on the distributor there is in the car. If it is a SVDA distributor (single vacuum hose from the carb to the distributor vacuum can), the setting is 7,5 deg BTDC. If it has two vacuum hoses, the setting is 5 ATDC. If it has no vacuum unit (like 009), you set it by maximum advance.

Reply to
Karls Vladimir Peña

I had same problem and after trying EVERYTHING else I rebuilt the carb and it was fine. A carb need a good clean and rebuild every once in a while so give it a try. Takes less than half an hour.

Reply to
Michael Stevens

It is the correct distributor for my engine, but I think you're thinking in the right direction. The distributor was lying in my shed for a couple of years. I did removed the points plate and oiled that thing but the rest I left alone (I couldn't get the pin out of the bottom). I did check the movement of the cetrifugal mechanism, en it did move freely at the time. I even oiled it, but after a short run I saw the oil lying at the tin of the engine under de distributor, so maybe I didn't use the right oil (well... it was bycicle oil....). When I was adjusting the timing I got "funky" results, the timing mark jumped a bit, it wasn't constant.

Thanks for your responses.

Gerrelt.

Reply to
beetle boy

I allready got the rebuild kit at home, I was planning to do that.

So, I'll give it a try.

Thanks for your response.

Gerrelt.

Reply to
beetle boy

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